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Manure in Trailers

The second phase of the trailer disinfection research project is well underway, which involves testing a vacuum system combined with high-pressure washing. Photo by Contributed photo

The presence of Porcine Epidemic Diarrhea Virus (PEDv), which appeared in the U.S. in April 2013 and in Canada in January 2014, presents tough challenges for manure managers.

In a guide called Biosecure Manure Pumping Protocols for PEDv Control, published by the U.S. National Pork Board and partners, it states that “PED virus transfers via feces and survives in manure for extended periods of time. Any object that becomes contaminated with pig manure can be a source of infection.”

One of those objects is, of course, swine transport trailers. That’s why a group of researchers at the University of Saskatchewan (U of S) in Saskatoon are evaluating a combination of methods to ensure complete disinfection of trailers in order to reduce the risk of disease exposure. There is a wide range of pathogens that can be spread from organic material left in a transport vehicle, including PEDV, PRRSV, PCV, S. suis, brachyspira and many more. The initiative is part of a multiphase project being conducted on behalf of Swine Innovation Porc.

“Industry came along and said that they are spending a significant amount of time and money to clean their trailers, but that they’re not sure if the trailers are clean enough,” says lead investigator Dr. Terry Fonstad, with the college of engineering at the U of S. “There are nooks and crannies that exist, and it’s hard to know if they are completely disinfected. So, the goal of our project is to develop an easier and more efficient process to disinfect trucks and save the producers some real money.”

While trucking companies do their best to wash out trailers extremely well, Fonstad notes that solid data is needed on what works best.

“We’ve got larger companies with top-notch systems to clean trailers and they let them sit to completely dry and several days before the next use,” he explains. “But it’s hard for smaller haulers to make money with a trailer that may take six to eight hours to clean and then is out of use while it totally dries. If we have an efficient method that kills all pathogens and reduces the cleaning time, everyone will benefit. Even supposedly clean trucks at the border going either way could be treated again as a reassurance.”

Fonstad says effective cleaning of a trailer means ensuring that – whatever means are being used – there is enough contact time between the disinfectant and the pathogen. He notes that if there is a piece of manure stuck somewhere, the pathogen is protected in that material, and it doesn’t matter what disinfectant you use if there isn’t adequate contact between the disinfectant and pathogen. “The larger the clump, the harder it is to get to the middle of it, to heat it or get rid of it,” he explains. “You can even use just hot dry heat, but if there is thicker crust or pieces of material, you have to have longer heating time. So, we first need to know exactly what is required to completely destroy the viruses and bacteria, and then develop a method that works when you test it on a truck with real world conditions.”

Phase 1, a look at current technologies, is now complete. “Dr. Volker Gerdts and colleagues at the Prairie Swine Center completed a literature review and found all microbes may be destroyed when exposed to 70°C for at least 10 minutes,” Fonstad says. “Of course, if we could heat the whole trailer to that temperature for that long, we could safely say that trailers were clean. But we need to determine the feasibility of heating livestock trailers to these temperatures, or we needed to come up with something that would achieve the same results.”

Phase 2 of the project is well underway, which involves testing a vacuum system combined with high-pressure washing. Researchers at the Prairie Agricultural Machinery Institute (PAMI) in Humdoldt, Sask., are part of the team and tested various vacuum systems with different-sized hose ends, and the results were very good. The team ended up designing a dual head that looks like a carpet-cleaning vacuum head combined with a high-pressure water system outlet.

Fonstad notes that the head provides several benefits, including the fact that it uses significantly less water than a standard high-pressure water hose.

“Because of the vacuum aspect, it also works in such a way that all the manure and water can be contained within the system,” he notes. “This is obviously cleaner for the surroundings and it’s also faster than cleaning a trailer by just hosing it out.”

Right now, the system is manual, but the team plans to develop a set of tools that could automate the process to some extent, with the ultimate goal of a fully-automated system.

“We also need to look at the impact of the system on the trailer parts,” Fonstad explains. “We can’t have a system that impacts airlines, and whether heating a trailer to that temperature and then putting it out in the cold will cause undue damage.

“The system can then be taken and marketed by a commercial partner, eventually,” he adds. “We suspect it will have other applications outside of swine transport.”

When asked if more inspection should be done on transport trailers to make sure pieces of metal haven’t become bent and so on (thereby creating new places where manure could get stuck), Fonstad answers: Yes.

“It would be a good master’s graduate student project, to look at this inspection aspect and to look at trailer design. There are probably some opportunities to add a panel or welding a piece here or there to prevent manure from getting into nooks and crannies and corners.”

However, Fonstad sees a need for a better, more permanent long-term solution in the future.

“Yes, we can likely do all kinds of things with existing trailers to prevent opportunities for pathogens to hide, but ultimately down the road, we need to look at an improved transport system,” he says. “It could be improved trailers or crates or something else, dedicated swine transport containers that can be put through automated washing machines.”

Manure trailer ventilation
Dr. Bernardo Predicala has been working to design, develop, and evaluate an air filtration system for swine transport trailers to better protect pigs from airborne pathogens. Predicala manages the Engineering Research Program at the Prairie Swine Centre in Saskatoon, Sask. and is also an adjunct professor in the department of chemical and biological engineering at the University of Saskatchewan.

The final design (composed of an axial fan, pre-filter combined with high-efficiency filter, air inlets, and air exhaust vents with shutter) was installed on a commercial swine gooseneck transport trailer, and tested for its ability to maintaining a pathogen-free environment.  

Predicala says fabric bag filters performed better than the MERV 16 filters, but are more expensive. In his view, “there would be situations wherein MERV 16 filters are sufficient (e.g. short-haul trips, low risk of airborne infection along the route, relatively low potential losses), but for situations where higher risk is involved and the loss potential is large (e.g., transporting high-value breeding stock through routes with high pig density), fabric bag filters would be more suitable.”

With regard to trailer filtration systems in general, Predicala recommends the installation of an environmental controller to better regulate the temperature inside the trailer (for animal comfort), and also using a temperature-monitoring/carbon dioxide detection system with an alarm detectable in the truck cab.

“You also want to avoid high fan static pressure,” Predicala adds. “It leads to more work by the fan motor to deliver the needed airflow, and consequently uses more power.”

One way to reduce fan static pressure is to provide larger openings for the air to flow through such as the inlet, the filter area as well as the exhaust vents.

Research team

• Terry Fonstad, Ph.D, P.Eng. – (Team Lead) – College of Engineering, University of Saskatchewan
• Volker Gerdts, Ph.D. – (Pathogen Lead) – Associate Director (Research), Chief Science Officer, VIDO-InterVac, University of Saskatchewan
• Hubert Landry, Ph.D., P.Eng – (Machinery Lead) – Project Manager – Agricultural Services,  Prairie Agricultural Machinery Institute
• Denise Beaulieu, Ph.D. – (Pathogen Reviewer) – Research Scientist – Nutrition, Prairie Swine Center, University of Saskatchewan
• Neil Ketilson, BSA – (Industry Lead) – General Manager, SaskPork